Buscemi Francesco, Chitambar Eric, Zhou Wenbin
Graduate School of Informatics, Nagoya University, Chikusa-ku, 464-8601 Nagoya, Japan.
Department of Electrical and Computer Engineering, Coordinated Science Laboratory, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, USA.
Phys Rev Lett. 2020 Mar 27;124(12):120401. doi: 10.1103/PhysRevLett.124.120401.
Measurement incompatibility describes two or more quantum measurements whose expected joint outcome on a given system cannot be defined. This purely nonclassical phenomenon provides a necessary ingredient in many quantum information tasks such as violating a Bell inequality or nonlocally steering part of an entangled state. In this Letter, we characterize incompatibility in terms of programmable measurement devices and the general notion of quantum programmability. This refers to the temporal freedom a user has in issuing programs to a quantum device. For devices with a classical control and classical output, measurement incompatibility emerges as the essential quantum resource embodied in their functioning. Based on the processing of programmable measurement devices, we construct a quantum resource theory of incompatibility. A complete set of convertibility conditions for programmable devices is derived based on quantum state discrimination with postmeasurement information.
测量不相容性描述的是两个或更多量子测量,其在给定系统上的预期联合结果无法被定义。这种纯粹的非经典现象是许多量子信息任务中的必要要素,比如违反贝尔不等式或对纠缠态的一部分进行非局域操控。在本信函中,我们依据可编程测量设备以及量子可编程性的一般概念来刻画不相容性。这指的是用户在向量子设备发布程序时所具有的时间自由度。对于具有经典控制和经典输出的设备,测量不相容性表现为其运行过程中所体现的基本量子资源。基于可编程测量设备的处理过程,我们构建了一个关于不相容性的量子资源理论。基于带有测量后信息的量子态判别,推导出了可编程设备的一套完整的可转换条件。